Lever-escapement.



W. J. SHORTILL.

LEVER ESGAPEMENT.

APPLICATION FILED DBO. 22. 1910.

037 342 I Patented Sept. 3, 1912.

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W. J. SHORTILL. LEVER ESGAPEMENT.

APPLIOATION FILED 1150.22. 1910.

Patented Sept. 3, 1912.

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COLUMBIA PLANOORAPN 1:0,, WASHINGTON, D. c.--

WILLIAM J. SHORTILL, OF MARI (DALE, ONTARIO, CANADA.

LEVER-ESCAPEMENT.

Application filed December 22, 1910.

To all whom it may concern:

Be it known that I, lViLLIAM J. SHORTILL, of the village of Markdale, in the county of Grey and Province of Ontario, Canada, have invented certain new and useful. Improvements in Lever-Escapements; and I hereby declare that the following is a full, clear, and exact description of the same.

The object of my invention is to devise a lever escapcnient in which the pallets are attached to the pallet lever between the fork and pallet center, to move across the primitive circle of the escape wheel as the pallet lever oscillates under the impulse of the escape wheel and balance, the escape wheel being provided with escape teeth perpendicular to its side faces to engage with the pallets and control the isoohronal intermittent movement of the escape wheel as hereinafter set forth and particularly pointed out in the claim.

For an understanding of the invention reference is to be had to the following description and to the accompanying drawings in which:

Figure l, is a plan view of my lever escapement showing the general construction and position of the related parts. Fig. 2, is a perspective view of the escape wheel. Fig. 3, is a perspective view of the pallet lever and pallets, and Fig. 4, is a diagrammatic view of the lever escapement.

Like characters of reference refer to like parts throughout the specification and drawings.

As my present invent-ion relates only to the escape wheel, pallet lever, and pallets, and to the relative position and movement of the latter with regard to the primitive circle of the escape teeth, it will, therefore, not be necessary to specifically describe any of the other parts of the lever escapement.

The escape teeth a a, instead of projecting peripherally from the rim of the escape wheel Z), project perpendicularly to its side faces, the escape teeth a being on one side of the escape wheel, and the escape teeth a on the other side. The locking face (Z of each escape tooth a passes to one side of the escape center 0 and that of each escape tooth 6/ passes to the other side of the escape center as shown in Fig. l. Likewise the angular-lines of the lifting faces 6 of the two sets of escape teeth pass to opposite sides of the Specification of Letters Patent.

Patented Sept. 3,1912.

Serial No. 598,866.

tangential line h drawn from the pallet center to the primitive circle.

I find that satisfactory results can be ob tained by arranging each locking face (Z at an angle of twenty four degrees to a radial line drawn from the escape center to the locking corner (Z of the escape tooth, and by arranging each lifting face 6 at an angle of three degrees to the tangential line it, these angles being taken at the place where the pallets 7: 7t" cross the primitive circle. The pallets 7c 7:, attached to the pallet lever 2' oscillating from the pallet center j, are arranged in two different horizontal planes, as shown in Fig. 3, with suflicient clearance between them for the free revolution of the escape wheel. The angles of the lifting faces Z of the pallets correspond with the angles of the lifting faces of the escape teeth, and likewise the angles of the locking faces Z of the pallets correspond with those of the escape teeth.

One end of the pallet lever i is provided with a fork m engaging with the impulse pin 0 of the balance 2) and the pallets l0 K2 are attached to the pallet lever between the fork and the pallet center to move to the right and left of the primitive circle as the pallet lever oscillates under the impulse of the escape wheel. lVhen the balance is swinging to the right, the impulse pin 0 engages the fork m/ moving it through a small arc and turning the pallet lever to the right of the pallet center j. This movement dis engages the locking face of the inside pallet it from the locking face of an escape tooth a and when the locking faces of the inside pallet 12' and the escape tooth a are disen-.

gaged, their lifting faces come into contact, throwing the pallet 73 and pallet lever farther to the right, causing the fork of the pal let lever to throw the balance wheel to the limit of the right oscillation, and bring the locking face of the pallet 70 fully into the path of the next escape tooth a.

Coincident with the disengagement of the pallet 70 and escape tooth a, the escape wheel moves forward until. the locking face of the escape tooth a engages with that of the pallet 70, and causes the arrest of the escape wheel until the isochronal swing of the balance moves the pallet lever to the left, disengaging the locking face of the pallet 70 from that of the escape tooth a and bring ing the locking corner 70 of the pallet 70' into position to again engage the neXt escape tooth a. The lifting face of the escape tooth a then engages with that of the pallet is, throwing the pallet 70 and pallet lever farther to the left and causing the fork of the pallet lever to throw the balance to the limit of its left oscillation, the escape wheel then moving forward until the locking face of the next escape tooth a engages with the locking face of the pallet k, which is then fully in the path of the escape tooth. During the isochronal oscillation of the balance, the pallets 7a 70 move on parallel arcs intersecting the primitive circle of the escape wheel, one pallet being positioned to engage the next escape tooth on its respective side of the escape wheel, before the lifting face of the other pallet is disengaged from the escape tooth on its respective side.

By providing the escape wheel with two sets of escape teeth and interrupting its rotation by the direct action of two pallets moving unitedly across the primitive circle, I am able to arrange for the escape at a small angle of vibration, and obtain a uniform isochronous movement of the parts.

The pallets 72 71: move in a plane parallel. with the side faces of the escape wheel to provide for the free revolution of the latter between them, and the escape teeth of one side of the escape wheel are staggered with respect to those on the other side, the pitch of both sets of escape teeth being the same, so that the intermittent rotation of the escape wheel will be uniform.

Having thus fully described my invention what I claim as new and desire to secure by Letters Patent is In a lever escapement, a balance having an impulse pin, a pallet lever oscillating from a pallet center and having at one end a fork to engage with the impulse pin, an escape wheel comprising two sets of escape teeth projecting perpendicularly from the side faces of the escape wheel, each escape tooth having a locking face and a lifting face, the locking faces of the escape teeth on one side of the escape wheel passing to one side of the escape center and the locking faces of the escape teeth on the other side of the escape wheel passing to the opposite side of the escape center with the angular lines of the lifting faces of the two sets of escape teeth passing to opposite sides of a tangential line drawn from the pallet center to the primitive circle of the escape wheel, and two pallets attached to the pallet lever between the pallet center and the fork, said pallets being arranged in two different horizontal planes with sufficient clearance between them for the free revolution of the escape wheel, each of the pallets being provided with lifting and locking faces, the angles of which correspond with those of the lifting and locking faces of the escape teeth.

Markdale, 6th December 1910.

WILLIAM J. SHORTILL.

Signed in the presence of KENDALL R. IIASKETT, CARMAN R. KING.

Ccpies of this patent may be obtained for five cents each. by addressing the Commissioner of Patents, Washington, D. G. 

